Quantum dot technology to advance molecular cell imaging

Researchers from the University of Illinois at Urbana-Champaign bioengineering team and Mayo Clinic have engineered a new type of molecular probe that can measure and count RNA in cells and tissue without organic dyes. The probe is based on the conventional fluorescence in situ hybridization (FISH) technique, but it relies on compact quantum dots to illuminate molecules and diseased cells rather than fluorescent dyes. This research is published in Nature Communications.

Quantum dots illuminate the locations of individual mRNA as red dots in the cytoplasm of a single HeLa cell. The blue region is the nucleus.  Credit: University of Illinois at Urbana-Champaign Department of Bioengineering

Over the last 50 years, fluorescence in situ hybridization technique has evolved into a multi-billion-dollar industry because it effectively images and counts DNA and RNA in single cells. However, fluorescence in situ hybridization technique has its limitations due to the delicate nature of the dyes. For example, the dyes rapidly deteriorate and are not very good at imaging in three dimensions. In addition, conventional fluorescence in situ hybridization technique can only read out a couple of RNA or DNA sequences at a time. Using quantum dots, however, can illuminate the locations of individual mRNA as red dots in the cytoplasm of a single HeLa cell.

The team created unique quantum dots that are made of a zinc, selenium, cadmium, and mercury alloy and are coated with polymers. “The core of the dot dictates the wavelength of emission, and the shell dictates how much light will be given off,” said Smith, who is also affiliated with the Micro + Nanotechnology Lab, Carle Illinois College of Medicine, and Department of Materials Science and Engineering at the University of Illinois.

These dots can emit color independent of the size of the particle, which is not the case for conventional quantum dots. The dots are also small enough (7 nanometers) to fit on a probe that can maneuver between proteins and DNA in a cell, making them more comparable in size to the dyes used in conventional FISH probes.

In experiments with HeLa cells and prostate cancer cells, the researchers found that dye-based FISH cell counts declined rapidly in minutes. The quantum dot-based FISH method provided long-term luminescence to allow counting of RNA for more than 10 minutes, making it possible to acquire 3D cell imaging.

Citation: Liu, Yang, Phuong Le, Sung Jun Lim, Liang Ma, Suresh Sarkar, Zhiyuan Han, Stephen J. Murphy, Farhad Kosari, George Vasmatzis, John C. Cheville, and Andrew M. Smith. “Enhanced mRNA FISH with Compact Quantum Dots.” Nature Communications 9, no. 1 (2018). doi:10.1038/s41467-018-06740-x.

New vaccine shown promise in preventing secondary strokes after an ischemic stroke

New research published in journal Hypertension shows that vaccine called S100A9 may be able to replace oral blood thinners to reduce the risk of secondary strokes in patients with recent ischemic stroke.

Japanese researchers successfully tested an experimental vaccine in mice and found that it provided protection against blood clots for more than two months without increasing the risk of bleeding or causing an autoimmune response.

The vaccine, S100A9, inhibits blood clot formation and, during the study, protected the arteries of treated mice from forming new clots for more than two months, and additionally, worked as well as the oral blood thinner clopidogrel in a major artery, according to Hironori Nakagami, M.D., Ph.D., study co-author and professor at Osaka University, in Japan.

“Many stroke patients don’t take their blood thinning drugs as prescribed, which makes it more likely they will have another stroke. This vaccine might one day help solve this issue since it would only need to be injected periodically,” Nakagami said.

Citation: Tomohiro Kawano, M.D.; Munehisa Shimamura, M.D., Ph.D.; Tatsuya Iso, M.D., Ph.D.; Hiroshi Koriyama, M.D., Ph.D.; Shuko Takeda; Tsutomu Sasaki, M.D., Ph.D.; Manabu Sakaguchi, M.D., Ph.D.; Ryuichi Morishita, M.D., Ph.D.; and Hideki Mochizuki, M.D., Ph.D.
https://doi.org/10.1161/STROKEAHA.118.022837

Late night snack with cottage cheese has no major adverse metabolic effects

Associate Professor of Nutrition, Food and Exercise Sciences Michael Ormsbee and former Florida state university graduate student Samantha Leyh found that consuming 30 grams of protein about 30 minutes before bed appears to have a positive effect on muscle quality, metabolism, and overall health. They compared protein from whole food (cottage cheese) versus liquid protein shake and placebo. In their results they showed no difference between whole food and liquid protein shake in terms of appetite and metabolic changes. Research suggests that no adverse impact of pre-sleep protein on metabolic activity. Research findings are published in the British Journal of Nutrition.

Study participants active young women in their early 20s ate samples of cottage cheese 30 to 60 minutes before bedtime. Researchers specifically wanted to see if this food may have an impact on the metabolic rate and muscle recovery.

“Until now, we presumed that whole foods would act similarly to the data on supplemental protein, but we had no real evidence,” Ormsbee said. “This is important because it adds to the body of literature that indicates that whole foods work just as well as protein supplementation, and it gives people options for presleep nutrition that go beyond powders and shaker bottles.”

Leyh, who is now a research dietitian with the Air Force, said the results serve as a foundation for future research on precise metabolic responses to whole food consumption.

Ormsbee said that his research team will start examining more presleep food options and longer-term studies to learn more about the optimal food choices that can aid individuals in recovery from exercise, repair and regeneration of muscle and overall health.

Citation:Leyh, Samantha M., Brandon D. Willingham, Daniel A. Baur, Lynn B. Panton, and Michael J. Ormsbee. “Pre-sleep Protein in Casein Supplement or Whole-food Form Has No Impact on Resting Energy Expenditure or Hunger in Women.” British Journal of Nutrition120, no. 9 (2018): 988-94. doi:10.1017/s0007114518002416.

Preventing Alzheimer’s dementia with Ibuprofen

Researchers suggest that daily intake of nonsteroidal anti-inflammatory drugs like over the counter ibuprofen could prevent the onset of Alzheimer’s disease. This research is led by Dr. Patrick McGeer and is published in the Journal of Alzheimer’s Disease.

Alzheimer’s dementia affects those diagnosed and their family along with a significant financial burden on the society. It is estimated around 47 million people worldwide are affected by this and is the fifth leading cause of death in those aged 65 and above. The Alzheimer’s Association estimates that there are more than 5 million cases in the United States alone. The annual cost United States in 2017 is estimated to be around $259 billion and the projected for the costs go to 1.1 trillion by 2050.

According to the latest publication by Dr. Patrick McGeer diagnosis of people at risk of Alzheimer’s disease is possible with positron-electron microscopy for AD senile plaques, blood or saliva analysis for the elevation of the amyloid-β protein fragment terminating at position 42, and cerebrospinal fluid analysis showing a decrease in the content of this protein. The publication also suggests prevention strategies like self-treatment by consumption of non-steroidal anti-inflammatory drugs, adhering to a Mediterranean diet, and consuming antioxidants such as quercitin which is contained in coffee.

Reference: Mcgeer, Patrick L., and Edith Mcgeer. “Conquering Alzheimer’s Disease by Self Treatment.” Journal of Alzheimers Disease, 2018, 1-3. doi:10.3233/jad-179913.

Adapted from press release by IOS press.

Improvements in optical mammography to advance breast cancer diagnostics

Researchers from Politecnico di Milano, Italy report improvements in the design of optical mammography used in diagnosis and monitoring of breast cancer.  They report increase sensitivity by a thousandfold.This research is presented at Biomedical Optics meeting 2018.

Schematic diagram of new and improved optical mammography device.
Credit: Edoardo Ferocino

Optical mammography uses infrared light and is used in conjunction with x-rays. It is optimal in cases needing repeated imaging to prevent high amounts of radiation associated with the regular procedure. Optical mammography can be used to measure blood volume, oxygenation, lipid, water and collagen content for a suspicious area identified through standard X-ray imaging. However, there are limitations to using optical mammography, which includes poor spatial resolution.

New improvements include using eight channel silicon photomultipliers (SiPMs) and multichannel time-to-digital converter instead of two photomultiplier tubes (PMTs) in existing optical mammography instruments. These changes eliminate the pre-scan step that was required to avoid damage to the photomultiplier tubes. In addition to increased sensitivity, the new instrument is both more robust and cheaper.

The investigators in Milan are working with a larger consortium on a project known as SOLUS, “Smart Optical and Ultrasound Diagnostics of Breast Cancer.” This project is funded by the European Union through the Horizon 2020 Research and Innovation Program and aims to combine optical imaging methods with ultrasound to improve specificity in the diagnosis of breast cancer.

Adapted from press release by the Optical Society.

Home genetic tests: how accurate are they?

Researchers at Ambry Genetics Corp analyzed how accurate direct-to-consumer genetic tests are in highlighting specific genetic variants. They found test raw data was incorrectly reported and could not be verified by further diagnostic laboratory tests in around 40% of the cases. These findings based on a small sample of 49 patients are reported in journal Genetics in Medicine.

Direct-to-consumer genetic tests (DTC) or home genetic tests are not diagnostic but are usually available to uncover information about ancestry, the risk of developing certain conditions and to check if they are a carrier to specific autosomal recessive conditions.  Home genetic tests are regulated by Food and Drug Administration, which currently prohibit these companies from offering diagnostic genetic tests. While they are not diagnostic some of the companies can provide raw data that can be interpreted by the third party for a fee.

Research led by Tandy-Connor and her colleagues set out to assess how accurate home genetic tests were in highlighting the presence of specific genetic variants. They analyzed the raw data of 49 patients that were referred to Ambry Genetics Corp for confirmatory testing, after sharing their home genetic tests raw data results with their medical providers. They found that two out of every five results were incorrectly reported and could not be further verified.

“Such a high rate of a false positives in this particular study was unexpected,” says Tandy-Connor, who believes that some of the discrepancies in the results can be explained by technical differences between the various testing methods used. “While direct-to-consumer genetic test results may lead to healthy changes in lifestyle or diet, these could also result in unwarranted emotions, including anxiety when someone obtains unexpected information, inaccurate information, or disappointment when receiving a lack of comprehensive diagnostic analysis.”

“The relatively small cohort simply reflects the reality that most people who get such direct-to-consumer genetic test results don’t seek confirmatory testing,” says Tandy-Connor. “People may assume that they are being provided accurate medical grade testing, so understandably do not go to the trouble and expense of seeking confirmation.”

Reference: Tandy-Connor, Stephany, Jenna Guiltinan, Kate Krempely, Holly Laduca, Patrick Reineke, Stephanie Gutierrez, Phillip Gray, and Brigette Tippin Davis. “False-positive Results Released by Direct-to-consumer Genetic Tests Highlight the Importance of Clinical Confirmation Testing for Appropriate Patient Care.” GENETICS in MEDICINE, 2018. doi:10.1038/gim.2018.38.

Adapted from press release by Springer.

Pecan consumption linked to improved cardiovascular and diabetic biomarkers

Researchers have conducted a study to see if eating pecans had an impact on cardiovascular disease and diabetes biomarkers. This study was funded by National Pecan Shellers Association and findings are published in journal Nutrition.

Researchers conducted a placebo-controlled crossover trial of 26 subjects. All subjects were provided with meals to carefully control their food intake. For 4 weeks one group had a diet with 15% of daily calorie intake provided with pecans. Both the control diet and the pecan-rich diet were low in fruits, vegetables, and fiber. Calorie levels, as well as protein, carbohydrate, and total fat, were kept the same. Results of the study showed improvements in serum insulin, insulin resistance, pancreatic beta cell function and cardiovascular disease biomarkers.

“Pecans are naturally high in monounsaturated and polyunsaturated fats, so replacing a portion of the saturated fat in the diet with these healthier fats can explain some of the cardioprotective effects we observed,” said lead researcher, Diane McKay, Ph.D. “But pecans also contain a number of bioactive plant compounds as well as vitamins and essential minerals that all likely contributed to this benefit. What’s really interesting is that just one small change – eating a handful of pecans daily – may have a large impact on the health of these at-risk adults.”

Reference: Mckay, Diane, Misha Eliasziw, C. Chen, and Jeffrey Blumberg. “A Pecan-Rich Diet Improves Cardiometabolic Risk Factors in Overweight and Obese Adults: A Randomized Controlled Trial.” Nutrients 10, no. 3 (2018): 339. doi:10.3390/nu10030339.

Research funding: National Pecan Shellers Association

Adapted from press release by Kellen Communications.

Muscular dystrophy treatment with Tamoxifen and Raloxifene

Researchers study the use of selective estrogen receptor modulators tamoxifen and raloxifene in patients with muscular dystrophies (MD). Results in an animal study showed significant improvement muscular function. The study findings are published in journal American Journal of Pathology.

Animal study results showing improvement in grip strength, running and changes in muscle histology following use of tamoxifen, and raloxifene. Credit: The American Journal of Pathology.

Selective estrogen receptor modulators have been used for their anti-inflammatory, antifibrosis, prevention of bone loss, and muscle building effects. The investigators found several indicators that tamoxifen and raloxifene delay or even halt disease progression. Within one month,  mice treated with either tamoxifen or raloxifene reduced muscle pathology with a significant reduction in the numbers of degenerating fibers. In one year treated mice show significantly lower histological changes compared to control group which showed high variation in muscle fiber size with focal inflammatory infiltrations.

These histological changes were accompanied by functional improvements in grip force production, extended running time and distance in a treadmill test, and enhancement in cardiac and respiratory functions.

“Our results show that there are two important advantages of tamoxifen and raloxifene treatment over steroids, which have limited benefits for patients with muscular dystrophies. First, the selective estrogen receptor modulators improve both histology and function of all muscles; although steroids improve histology, they improve function to a much lesser extent. Second, selective estrogen receptor modulators enhance bone density, whereas steroids exacerbate osteoporosis and increase the risk for fractures,” explained Qi Long Lu, MD, PhD, director of the McColl-Lockwood Laboratory for Muscular Dystrophy Research, Neuromuscular/ALS Center, Department of Neurology, Atrium Health’s (formerly Carolinas HealthCare System’s) Carolinas Medical Center, Charlotte (NC).

“selective estrogen receptor modulators therapy has great potential to significantly delay or halt muscular dystrophies progression. With the vast amount of safety data available, the selective use of tamoxifen and raloxifene in male and female patients with muscular dystrophies is an attractive and realistic alternative to steroids,” noted Dr. Lu.

Reference: Wu, Bo, Sapana N. Shah, Peijuan Lu, Lauren E. Bollinger, Anthony Blaeser, Susan Sparks, Amy D. Harper, and Qi L. Lu. “Long-Term Treatment of Tamoxifen and Raloxifene Alleviates Dystrophic Phenotype and Enhances Muscle Functions of FKRP Dystroglycanopathy.” The American Journal of Pathology 188, no. 4 (2018): 1069-080. doi:10.1016/j.ajpath.2017.12.011.

Research funding: Carolinas Muscular Dystrophy Research Endowment at the Carolinas HealthCare Foundation.

Adapted from press release by Elsevier.

Age-related macular degeneration treated with a stem cell retinal patch

Researchers developed retinal eye patch made from human embryonic stem cells to treat age-related macular degeneration. Researchers grew retinal pigment epithelial cells from stem cells and used synthetic basement membrane to create a retinal patch. Phase 1 clinical trial findings are reported in the journal Nature Biotechnology.

Age-related macular degeneration is the most common cause of visual impairment in the developed world. This condition usually affects people over 50 years. Age-related macular degeneration affects central vision.

The phase 1 study investigated if the stem cell retinal patch could restore vision by regenerating diseased cells. They surgically implanted the patch into the eye of two subjects. Results showed noted improvement in vision over 12 months. Further testing using biomicroscopy and optical coherence tomography showed that stem cell retinal patch survived.  To prevent tissue rejection they had to use local immunosuppression.

“This study represents real progress in regenerative medicine and opens the door on new treatment options for people with age-related macular degeneration,” said co-author Peter Coffey, a professor at UCSB’s Neuroscience Research Institute and co-director of the campus’s Center for Stem Cell Biology & Engineering.

Reference: Cruz, Lyndon Da, Kate Fynes, Odysseas Georgiadis, Julie Kerby, Yvonne H. Luo, Ahmad Ahmado, Amanda Vernon, Julie T. Daniels, Britta Nommiste, Shazeen M. Hasan, Sakina B. Gooljar, Amanda-Jayne F. Carr, Anthony Vugler, Conor M. Ramsden, Magda Bictash, Mike Fenster, Juliette Steer, Tricia Harbinson, Anna Wilbrey, Adnan Tufail, Gang Feng, Mark Whitlock, Anthony G. Robson, Graham E. Holder, Mandeep S. Sagoo, Peter T. Loudon, Paul Whiting, and Peter J. Coffey. “Phase 1 Clinical Study of an Embryonic Stem Cell–derived Retinal Pigment Epithelium Patch in Age-related Macular Degeneration.” Nature Biotechnology, 2018. doi:10.1038/nbt.4114.

Institutions involved in research

  • The London Project to Cure Blindness, ORBIT, Institute of Ophthalmology, University College London (UCL).
  • NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust, UCL Institute of Ophthalmology.
  • Moorfields Eye Hospital NHS Foundation Trust.
  • Wellcome/EPSRC Centre for Interventional & Surgical Sciences (WEISS), Charles Bell House.
  • Pfizer.
  • Cell and Gene Therapy Catapult.
  • Cells for Sight, Transplantation & Research Program, UCL Institute of Ophthalmology.
  • UCL Institute of Neurology.
  • Center for Stem Cell Biology and Engineering, NRI, UC, Santa Barbara.

Adapted from press release by the University of California Santa Barbara.

Study finds effectiveness of fasting diet (5:2 diet) in clearing fat

Researchers from the University of Surrey examined the effectiveness of the 5:2 diet vs. daily calorie restriction diet. They found that 5:2 diet clears triglycerides from blood quicker after eating meals. Their findings are published in British Journal of Nutrition reports.

The study divided overweight people into two groups. One group was assigned 5:2 diet another group was assigned daily calorie restriction diet. They measured days required for 5% weight loss, ability to clear fat and glucose from the blood. The 5:2 diet involved eating regularly for five days and restricting remaining 2 days to 600 calories per day.

Results of the study showed that subjects assigned to 5:2 diet lost 5% weight in 59 days compared other group which took 73 days. Researchers also found improved ability to clear triglycerides in this group. The study also found 9% reduction in systolic blood pressure by in 5:2 group.

Dr. Rona Antoni, Research Fellow in Nutritional Metabolism at the University of Surrey, said:

As seen in this study, some of our participants struggled to tolerate the 5:2 diet, which suggests that this approach is not suited to everybody; ultimately the key to dieting success is finding an approach you can sustain long term.

“But for those who do well and are able stick to the 5:2 diet, it could potentially have a beneficial impact on some important risk markers for cardiovascular disease, in some cases more so than daily dieting. However, we need further studies to confirm our findings, to understand the underlying mechanisms and to improve the tolerability of the 5:2 diet.”

Citation:  Antoni, Rona, Kelly L. Johnston, Adam L. Collins, and M. Denise Robertson. “Intermittent v. Continuous Energy Restriction: Differential Effects on Postprandial Glucose and Lipid Metabolism following Matched Weight Loss in Overweight/obese Participants.” British Journal of Nutrition 119, no. 05 (2018): 507-16. doi:10.1017/s0007114517003890.

Adapted from press release by the University of Surrey.